machinery

State-aware workflow orchestrator.

This project aims to bring stateful workflows, by defining a list of actions representing multiple microservices.

Define a suite of actions to process events, abstract intelligence for your microservices.

Once defined, use your workflows to process your Events.

Example

We have 3 microservices:

• The upper microservice that transforms texts into uppercase
• The reverse microservice that reverses a text
• The space-counter microservice that returns the number of space in a string

Suppose we want to process some text by making it uppercase and reversing it.

We will define the following definitions:

• examples/definitions/service-upper.json
• examples/definitions/service-reverse.json
• examples/definitions/service-space-counter.json

Then, we can define a Workflow in examples/definitions/workflow-process-text.json.

After having created our Workflow, we can send our first Event !

We will send the content of examples/definitions/event-text.json

Goals

• Register services (ex: a new API)
• Define a simple Workflow (subsequent calls to different services)
• Allow async (expose endpoint for webhook?)
• Visualisation

Components

API (WIP)

Could be divided into Consumer API and Management API.

• Register services
• Define Workflows (json with arbitrary service definition)
• Treat Event

Data structures

Service

{
    "name": "my-service-name",
    "address": "http://my-service:5000/",
    "spec": {
        "inputs": {
            "message": {
                "type": "string",
                "description": "The text to transform"
            }
        },
        "outputs": {
            "message": {
                "type": "string",
                "description": "The transformed text"
            }
        }
    }
}

input:

• name: The name of the Service
• address: The URL of the Service
• spec: The inputs/outputs of this Service
• spec.inputs: Each input with its type and description
• spec.outputs: Each output with its type and description

output: TBD (service-id, ack date)

Event

POST /e/<workflow-id>

{
    "data": {
        "message": "The Sun will rise in the morning !"
    }
}

POSTing an Event will return an event-id, an ack date and a status. input:

• data: The Event's data that must match the Workflow's inputs.

Workflow

{
    "name": "my-workflow",
    "spec": {
        "services": ["service-1", "service-2"],
        "inputs": {
            "message": {
                "type": "string",
                "description": "The text to process"
            }
        },
        "outputs": {
            "message": {
                "type": "string",
                "description": "The processed text"
            }
        },
        "operations": { }
    }
}

input:

• name: The name of the Workflow
• spec: The spec of the Workflow
• spec.services: The Services to be called, in order
• spec.inputs: The inputs of this Workflow
• spec.outputs: The outputs of this workflow

output: TBD (workflow-id, ack date)